Mems device having an improved cap and manufacturing process thereof
AssigneeSTMicroelectronics S.r.l.
InventorsSilvia NICOLI, Lorenzo TENTORI, Giuseppe BRUNO
Life of this patent
Estimating the term…
Abstract
The MEMS device has: a sensor body having a functional structure configured to transduce a physical or chemical quantity into a corresponding electrical quantity; and a cap bonded to the sensor body and having a first cavity overlying the functional structure. The cap has a supporting portion and a cover portion that form the first cavity. The supporting portion is bonded to the sensor body. The cover portion is bonded to the supporting portion and has an inner wall delimiting on a side the first cavity and facing the functional structure. The MEMS device further has a first coating that extends within the first cavity on the inner wall of the cover portion.
Claims20
A device comprising:
- a sensor body including a functional structure configured to transduce a physical or chemical quantity into a corresponding electrical quantity, the functional structure including:
- a first surface;
- a second surface opposite to the first surface;
- a first thickness that extends from the first surface to the second surface;
- a reference region including a first sensitive region, the reference region has the first thickness;
- a detection region including a second sensitive region, the detection region having the first thickness;
- a coupling region couples together the reference region to the detection region, the coupling region has an end surface spaced apart from the second surface, and the coupling region includes a second thickness that extends from the first surface to the end surface, the second thickness being greater than the first thickness;
- a cap bonded to the sensor body and having a first cavity overlying the functional structure, wherein the cap comprises a supporting portion and a cover portion that form the first cavity, the supporting portion being bonded to the sensor body, the cover portion being bonded to the supporting portion and having an inner wall delimiting on a side the first cavity and facing the functional structure;
- and
- a first coating extending within the first cavity on the inner wall of the cover portion.
A method, comprising:
- forming, in a device wafer, a functional structure configured to transduce a physical or chemical quantity into a corresponding electrical quantity;
- and
- forming a cap starting from a first cap wafer and a second cap wafer,
- wherein forming a cap comprises:
- forming a first coating on a surface of the first cap wafer;
- forming an opening in the second cap wafer;
- bonding the second cap wafer to the device wafer;
- and
- bonding the first cap wafer to the second cap wafer,
- so that the opening forms a first cavity that overlies the functional structure and the surface of the first cap wafer forms an inner wall of the cap that delimits on a side the first cavity and faces the functional structure.
A device, comprising:
- a sensor body including:
- a first cavity within the sensor body;
- a functional structure suspended over the first cavity, the functional structure including:
- a first surface;
- a second surface opposite to the first surface;
- a first thickness that extends from the first surface to the second surface;
- a reference region including a first sensitive region, the reference region has the first thickness;
- a detection region including a second sensitive region, the detection region having the first thickness;
- a coupling region couples together the reference region to the detection region, the coupling region has an end surface spaced apart from the second surface, and the coupling region includes a second thickness that extends from the first surface to the end surface, the second thickness being greater than the first thickness;
- a cap coupled to the sensor body, the cap including:
- at least one lens that overlaps the second sensitive region of the detection region;
- and
- a shielding region that overlaps the first sensitive region of the reference region.
Dependencies are inferred from the claim text.